Power amplifiers are used in many application areas, including industrial and consumer electronics. One such application involves the amplification of audio power supplied to output devices, such as loudspeakers. For many low power applications, field effect transistors (FET's) are typically used in amplifier circuits due to their relatively high-speed switching capability. However, FET's generally become power limited in applications where the operating voltage is in the range of approximately 200 volts or higher.
One electronic switching device capable of higher power operation (i.e., in excess of 200 volts) is the insulated gate bipolar transistor (IGBT). While the IGBT can be used at power levels in the kilowatt range, the device has a relatively slow switching speed, with a typical upper frequency limit of approximately 20 kHz. As such, conventional power amplifier circuits using IGBT's would generally be limited in frequency to approximately 20 kHz.
Other switching devices having higher power and frequency capabilities may be considered for this type of power amplifier application, but the cost of such devices is typically many times higher than the cost of a standard IGBT, making the high-cost devices generally undesirable for production applications. Furthermore, as technology advances, it can be assumed that there will be an ongoing demand for power amplifiers that are capable of operating at higher frequencies and higher power levels. For example, there are current applications for a loudspeaker power amplifier requiring an operating frequency in the range of 60 kHz, with a minimum power level of 8 kilowatts. Therefore, there is a need for an audio power amplifier system capable of operating at high frequency and high power levels. Moreover, this type of power amplifier could be suitable for production applications if the switching elements were standard low-cost components, such as IGBT's.
Accordingly, it is desirable to provide a power amplifier system for applications requiring high (audio) frequency and high power capabilities. In addition, it is desirable to implement the power amplifier system with low-cost components for production applications. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.